1. Field of the Disclosure
This disclosure relates to a liquid crystal display device capable of improving the response time of liquid crystal.
2. Description of the Related Art
Nowadays, image display devices driving pixels arranged in an active matrix shape have been widely researched. The image display devices include liquid crystal display (LCD) devices, organic electro-luminescent display (OLED) devices, and so on.
More specifically, the LCD device applies data signals, corresponding to image information, to the pixels arranged in the active matrix shape and controls the transmissivity of the liquid crystal layer so that the desired image is displayed. To this end, the LCD device includes a liquid crystal panel with the pixels arranged in an active matrix shape, and a drive circuitry driving the liquid crystal panel.
In the liquid crystal panel, gate lines and data lines are arranged to cross each other and pixel regions are defined by the gate lines and the data lines crossing. Each of the pixel regions includes a thin film transistor TFT and a pixel electrode connected to it. The thin film transistor TFT includes a gate electrode connected to the respective gate line, a source electrode connected to the respective data line, and a drain electrode connected to the respective pixel electrode.
The drive circuitry includes a gate driver sequentially applying scan signals to the gate lines and a data driver applying data signals to the data lines. As the gate driver sequentially applies the scan signals to the gate lines, the pixels on the liquid crystal panel are selected in the line unit. Whenever the gate lines are sequentially selected one by one, the data driver applies the data signals to the data lines. As such, the LCD device controls the transmittance of the liquid crystal layer by an electric field which is induced between the pixel electrode and a common electrode and corresponds to the data signal applied to each pixel. Accordingly, the LCD device displays an image.
In order to lower the manufacturing cost, an LCD device of an internal driver type has recently been developed which includes the gate driver and the data driver provided on the liquid crystal panel. In the LCD device of an internal driver type, the gate driver is simultaneously manufactured with the thin film transistors when the thin film transistors are formed on the liquid crystal panel. Meanwhile, the data driver may or may not be provided on the liquid crystal panel.
As the LCD device becomes larger in size, the gate lines lengthen by the increment of screen size so that line resistances increase. This results in the response time of the liquid crystal becoming slower due to the lowered changing rate of the thin film transistor.
In order to improve the response time of the liquid crystal, the channel region of the thin film transistor can be expanded. However, in the LCD device of an internal type, it is difficult to improve the charging rate of the thin film transistor due to an area limitation.